i think if you were to ask the folks in washington, they will tell you that there is a lot of behavior that while it was unethical and perhaps morally suspect didn't rise to the level of criminal conduct. >> reporter: is it sometimes just easier to go to the guy who is on the bottom of the food chain? >> it's certainly a lot easier, but that doesn't make it right. and it doesn't really accomplish the broader goals that you want from your department of justice in the aftermath of a crisis, and that's to make it very clear that if you break the law, if you do this type of unethical behavior that you will be held accountable. and all the charlie engles in the world rotting in jail aren't going to accomplish that goal. >> it may not surprise you to learn that charlie engle is petitioning for a new trial hoping to overturn his conviction. charlie still owes the banks $250,000 in restitution. >>> up next here tonight, on the trail of the man u.s. officials call the largest single threat to america. >>> and later, the pitfalls of four stars. life at the top of the military, according to those